No.
It means subject of a foreign country who still holds primary residence in that country or is an official agent of that state.
If you come to the US on vacation, and your wife goes into early labor and has a kid here, the kid is still a citizen of the country you came from.
If you sell everything you own in your home country, pack up your family, relocate them to the US, establish a home here, get a job, knock up your wife, and have a kid, he's an American.